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nmehdikh

EFI newb advice/question maybe ITBs?

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Car is a 73 240z, motor is an L26, will eventually see track time.

So, the car is currently running an edelbrock single carb, and pertronix ignition. Attached is a pic of the engine bay as it sits right now.

I'd like to move towards EFI, and possibly even COP for spark. So there are going to be a lot of dumb questions here, and I'd like some clarification if you guys can provide it. I'm an idiot and trying to learn as I go along :)

As of right now, I can think of two possible routes to go. If you guys have other ideas, I'm all ears.

1) pull off the edelbrock carb, and replace it with one of those four barrel EFI systems. Something like this. Find one that works off of megasquirt, and use the pertronix as a halls effect sensor? This requires just one 02 sensor in the exhaust correct? The air sensors are built into the four barrel EFI?

2) ITB route?  Get one of these. Then try to fab of motorcycle throttle bodies to it? Maybe off of a ZX-12R? What size would I need for the L26? For the motorcycle ITB route, is there only a single MAF or MAP? Or do I need to put one in each runner? Or are they usually built into the throttle body? How about o2 sensors? do they use use a single one as well? Or one per cylinder?

Sorry if these questions are basic/dumb. I'm trying to understand how all of this works.

post-54134-0-16240700-1486498902_thumb.jpg

Edited by nmehdikh

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Your questions are a decent step in to the world of EFI but yes, they are a bit odd.  A great starting point to learn about EFI is the Engine Fuel chapter of the 1975-1978 FSM's.  They give a very fundamental explanation of EFI because they were the first years of EFI for Nissan.  Seriosuly, download the 1976 FSM and read the Engine Fuel chapter.

 

On spark, there are many possibilities, but much of the very complex systems are really designed for emissions purposes, not performance.  The performance benefit to cost ratio isn't great for anyhting beyond a fairly modern electronic igntion system.  The Pertronix system is an early electronic system that has survived the years,   But there are simpler, chepaer ways to get a good stronger spark.  ZX distributors, GM HEI modules, MSD setups, etc.

 

If you want to make a big jump in to EFI, read up on Megasquirt.  The Megamanual is random and complex but there are some good writeups on different manufacturers' systems that can be very educational.  But you can get lost in there too.

 

Keep reading and posting focused questions and a path will show itself.  Good luck.

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I used to have a four barrel setup, it was ok. It has some advantages. But these motors are heavenly with the side draft carbs or ITB FI setup. My recommendation: save a little more and go for the ITBs. If you're going to spend what it takes to do this, Then go all out.

 

-ITB source: https://www.jenvey.co.uk. Convert $ to USD. Use the DCOE type to match the flange style on the intake.

-That Kameari intake is good. I think they sell the same one on eBay sometimes, maybe cheaper or free shipping?? Here's another source: http://www.gl2007.com/usa_23.html I have bought from them before, no problems.

-One O2 sensor is good - a bung welded in just after the header flange is fine.

-Not sure about what to do with a MAF. You probably need an intake box then run the MAF between that and a cone filter. I think Jenvey also has the air boxes.

 

When you think you have decided, add up all cost to do this. If your budget can't handle it, then be happy with what you have, or get a triple Weber kit. If you say "that's not that much $$$" then first compare to an RB25 SWAP it may not be all that much more.

Just my 2 cents

Edited by Samurai7one

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Solid information guys, I appreciate it and I'll do some more reading.

So far, what I learned regarding the ITB setup, I may be best served with a MAP sensor instead of a MAF. Plumbing the MAP sensor to a small plenum then to the individual runners.  Here is a pretty good read.

Regarding ITBs, and the Jenvey website you linked. I have two questions.
1) Whats the difference and purpose between the different bore types? Parallel bore, tapered bore etc.
2) How do I determine what size throttle bodies to use on the L26 if I am using 6 of them?

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Your Google-fu is strong. What's your objective?  Derek did some good stuff with ITB's and EFI.  Search his posts and you will be closer to the grasshopper..

Objective? Well I bought a 40 year old car for no good reason other than to burn through money and maybe learn a thing or two. Hopefully, with the added side effect of having a car that is fun to drive.

 

Realistically, I know a swap would probably be the easier/cheaper/ well documented route. But I like the L26, and I've been itching to learn more about EFI, and ITBs so this is a good excuse.

 

I saw a couple of Derek's posts about his new head he's been working on. I'll go dig through some of his other stuff.

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You say 'see track time'... 

 

Lets cut to the chase: Will you install FORGED PISTONS and put in a large camshaft to be able to rev to 8000 rpms?

 

If you are  running cast pistons  and the  engine will never see more than 7000, 7,400 keep your four barrel.

 

I bought my set of HKS 45 mm ITB's off a guy in the Bay Area who sniped them off me, and installed them on his 3.2 stroker. Thing was, it was a cast piston job like so many Americans cheap out on, and therefore  was limited to 7,000 rpms.

 

All said and done, he had minimal gains from the HKS with a lot of packaging issues that he didn't have when compared to his former four barrel setup.

 

so I bought the setup off of him, after he reinstalled his four barrel.

 

If anybody cares to recall, my testing back in the 90's revealed disparity after 6500 rpms when using the four barrel. With cast pistons, it will work fine. There will be a minimal performance gain.

 

If you build a proper L-Series, there will be no comparison hands down itbs will be the way to go. We were  up over  80HP over  our four barrel at 7,600, and even more at 8250 rpms when using ITBs over 45 DCOE or 4 Barrel.

 

If it's going to have cast pistons, and be limited to 7,000 rpms, save your money. Keep what you got. Or put an Atomic EFI on there. you can do an air door and Megasquirt if you think you can handle the tuning...just make sure  you set up the secondaries on a proper progression so you maintain a proper MAP signal and don't always drop to zero every time you touch the throttle pedal! You will thank me in fuel mileage remembering that...

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1) I have read about the bores in some posts here at hybridZ, but can't remember exactly what the pros/cons are. I want to say it's about the velocity of the air flow. The tapered bore may produce more with less turbulence???

 

2) 40-45 mm should be ok. but I would go with the larger option, with the expectation that eventually I would install in an L28. This is due to the availability of the L28 vs the L26. 40s would work just fine on the L28 also but you may not get the maximum potential top end hp.

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Tony D, the motor will eventually get forged pistons. It has a slightly aggressive cam right now. But I'm not really going to take it apart just yet, since it's running like a champ, but in the future yes.

Question about injector placement. I've read conflicting information about where exactly the injector should be located along the manifold. Closest to the head as possible? It's fine where it is now? (inside the motorcycle ITB)

And what about angle of the injector?

Off the top of their head, does anyone know the spacing on the intake manifold? The Daytona 675 throttle bodies can be easily taken apart and spaced to the proper distance, but I'm worried about minimum distance.
PdilLQy.jpg

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If you want to do this in stages while you keep driving the car then I would do ECU. My choice would be megasquirt. Get the ECU controlling the ignition. Then get your Lambda system going.  Then convert to EFI.  As Tony said the 4 barrel will serve you well but after tuning my car with a laptop I'll never go back to a carburetor. If you can cheaply convert the 4 barrel to a EFI unit then that would be the next step after getting your ignition running. So now you have your ignition and fuel system sorted out. If you are happy with the EFI 4 barrel then you are good to go. What you will have gained is modern control of your ignition and fuel system.  If you decide to go with ITBs then you better value the looks and sound as part of your justification. They are for sure more finicky and I ended up paying a tuner to help me get everything dialed in. Right now I'm sticking with what I have but at some point I will be switching over to the Jenvey Heritage bodies.

 

And if I had a Z with a 4 barrel I'd rip that thing off of there faster than Sh$iT through a goose.  Those things are butt ugly in my book:)

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Off the top of their head, does anyone know the spacing on the intake manifold? The Daytona 675 throttle bodies can be easily taken apart and spaced to the proper distance, but I'm worried about minimum distance.

 

 

I used 48mm GSXR ITBs to clamped to DCOE flanges, looks cool, but I really don't recommend it. Pedal throw without a very slow progressive throttle linkage is like half an inch from idle to full throttle. Anyway, it's really not worth the headache, get Jenveys. In the end, I might have saved $200, but had a million little headaches to deal with. Pics are in this thread.

 

If you still want to go down that route, DCOE spec is 90mm bore center and about 110mm bore center between the sets of carbs.

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I used 48mm GSXR ITBs to clamped to DCOE flanges, looks cool, but I really don't recommend it. Pedal throw without a very slow progressive throttle linkage is like half an inch from idle to full throttle. Anyway, it's really not worth the headache, get Jenveys. In the end, I might have saved $200, but had a million little headaches to deal with. Pics are in this thread.

 

If you still want to go down that route, DCOE spec is 90mm bore center and about 110mm bore center between the sets of carbs.

Thanks for the link. Wouldn't 48mm be too big for each one? Regarding pedal throw, that's valuable information. My car currently has a cable linkage, so it might be fairly easy to rig up a cam deal to make it more progressive.

 

@Derek - I agree with your staged approach and was planning on getting ignition going first, and making sure the ECU was reading all the inputs correctly before tackling EFI. When you say lambda system, do you mean just o2 sensor? Or am I missing something?

 

Regarding the ignition situation, can you look over this and see if I'm missing anything?

1) Crank sensor here and hall sensor here

2) 02 sensor + bung for header

3) megasquirt3 with MS3X expansion here

4) wiring harness for above here

5) LS2 truck coils, D585 (the ones that have the igniter built in)

6) pig tail connectors for the coils

7) short spark plug wire to go from LS2 coils to plugs

 

That should be enough to get me control of my ignition and see my o2 levels?

Edited by nmehdikh

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After reading my own thread the GSXR throttle bodies are actually 46mm. The opening is 48mm, but it necks down quite a bit. so it's the number that sticks out in my mind. My Jenvey ITBs are 48mm straight through though.

 

A 45mm throttle body is probably large enough for most things. If you know what you're doing (I don't necessarily) tuning the intake for a specific RPM range or output, there's probably a formula out there for optimum size. I just know from reading that with EFI, having a large throttle body won't hurt performance (nor will it necessarily gain any). I'm sure someone far more knowledgeable than me will come along.

 

Anyway, you seem to have everything else worked out in regards to Megasquirt. Good luck, it's a steep learning curve, but with MS3x, they've made it quite a bit easier.

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When you say lambda system, do you mean just o2 sensor? Or am I missing something?

 

 

My megasquirt 2 required a standalone lambda controller. I originally had a Innovate LC-1 and it was junk. My tuner recomended a 14point7 Spartan 2. I have been very happy with it so far and would highly recommend it.

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Thanks for the link. Wouldn't 48mm be too big for each one? Regarding pedal throw, that's valuable information. My car currently has a cable linkage, so it might be fairly easy to rig up a cam deal to make it more progressive.

 

@Derek - I agree with your staged approach and was planning on getting ignition going first, and making sure the ECU was reading all the inputs correctly before tackling EFI. When you say lambda system, do you mean just o2 sensor? Or am I missing something?

 

Regarding the ignition situation, can you look over this and see if I'm missing anything?

1) Crank sensor here and hall sensor here

2) 02 sensor + bung for header

3) megasquirt3 with MS3X expansion here

4) wiring harness for above here

5) LS2 truck coils, D585 (the ones that have the igniter built in)

6) pig tail connectors for the coils

7) short spark plug wire to go from LS2 coils to plugs

 

That should be enough to get me control of my ignition and see my o2 levels?

 

Maybe you should look at my MS3X install thread. Covers a lot of your requirements. I am currently converting to FI, but I have started with ignition. There's a lot involved to changing from carb to FI, but I am in the process now. I started another thread showing the transition. Maybe you can get some ideas. I am trying to lay the ground work for programmable FI by starting off with a stock FI intake , then get educated enough to program ITB's . It's a steep learning curve-put your climbing shoes on   

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I am currently doing a microsquirt with dizzy less wasted spark setup for my l28 race car (track only).

 

Very affordable but still very good.

 

Comes with a diy harness that makes it easy.

Things you need:

 

- TPS from 240sx (for Ms fuel)

- trigger wheel (diyautotune.com)

- hall sensor (diyautotune.com)

- fab a mount from sensor (where AC used to be)

 

The last step is the hardest, haven't figured out that yet.

 

I am using stock intake but you can buy better EFI intakes from lonewolfperformance.com

 

Good thing with race cars is that it simplifies the EFI a lot!

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Bumping an old thread with updates and seeking more advice as always. I guess this thread is going to devolve into a general build thread?

The megasquirt/ITB plan was put on hold for other things done to the car in the meantime. But finally getting around to getting the parts together.

Done :
1) upgraded the braking system : 4 piston fronts, and disks to the rear from silverminemotors
2) new floors from zed and new frame rails from baddog
3) added half cage and safety harnesses
4) new wheels and tires
5) all suspension bushings done

In progress :
1) Rewiring the entire car. A previous owner did a terrible job of installing a rats nest of a "painless" wiring harness.
2) New radiator and fans

To Do in the next couple months:
1) rebuild head
2) get megasquirt/EFI working

So here are some questions for you guys.

Regarding the head
I believe its an E88 that came with the L26, but I'll check tomorrow morning and make sure.
1) If I am going EFI and ITBs what cam do you recommend?
2) Rebuilding the head, I'll be taking it to a machine shop, but what do I need to buy for them to complete the work?
3) What are my options performance wise? Shave the head down to increase CR? how much?
Keep in mind, I live in CA so I only have access to 91 octane.


Regarding ITBs/Megasquirt
Going with MS3X with the expansion. Using the two harnesses from DIYautotune to make my life a little easier. Got 2 sets of triumph ITBs Off a 2012 675 Daytona, talking to the guys at DIYautotune and I should be able to reuse the TPS and ISCV from triumph. Going to use the lambda controller Derek recommended.
1) For Crank position and Cam position I was going to switch to the distributor from the 1982-1983 L28ET and use this trigger wheel. Will this distributor work with my 240z's tach? If so, how does it get wired in.
2) What size fuel pump and injectors will I need? I imagine I don't need anything too crazy right? 36lb/hr injectors?


Pics of the car as it currently sits in it's dirty state.

 

s-l1600 (5).jpg

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As much as I’d like to do ITB’s - I chickened out and went with a stock intake . Why? Because I have/had so much to learn about tuning and I didny want it to be overwhelming and not enjoy my ride .

that being said - maybe you should find a stock intake and I would recommend a Maxima head . Everything just bolts together and you can concentrate on learning to tune with MS instead of fighting an ITB set up

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With injectors a couple of notes.

 

Assuming staying Normally aspirated. 

 

1:  Stock  non- Turbo 188CC injectors will support up to 200 HP easily.  L28 Turbo injectors ( 265 cc ) will support up to 250hp.  300cc ( 30lb/hr ) will support 310 bhp at the crank at 90% IDC. 350cc will support 360BHP at the crank at 90% IDC.

 

http://fuelinjectorclinic.com/hp-calculator

 

2: I would strongly recommend either buying new or reman injectors. Or sending your present injectors out to a company like Injector Re-Hab to have them cleaned and flowed.

 

http://injector-rehab.com/shop/home.php

 

Motorman is a good place to buy re-man injectors

 

http://www.fuelinjector.citymaker.com/web_page.html

 

3: Injector impedance is very important. MS can run either, but it does have some quirks. If Low -Impedance injectors are used, I would advise keeping the stock dropping resistors. MS PWM current control limiting can be a PITA to configure with some injectors. The stock Nissan JEC's injectors are one of those brands that are " finicky ". The factory  dropping resistors  with Low-Z injectors and MS1/2 are much less troublesome. MS3 also has better Low-z driver software.

 

The other solution is to use Hi-Z injectors. This is what most modern cars use these days. May be a better choice if you plan on changing injectors and installing a Pallnet fuel rail. Will give you more selection in Injectors and Hi-Impedance injectors do not need dropping resistors nor PWM current limiting. If changing injectors and going non-barb hose style I would recommend getting Hi- Impedance with 14 mm Top and bottom O-Rings. This will give you a wide range of choice and you can use Bosch injectors that come with the Nissan style EV1 connector.  Get a single spray pattern such as used on Ford Mustangs etc. Dirt cheap from Motorman.

 

4: Downloading a Tune off the Internet is not a good idea. Even MSExtra Forums  warns against this. Every engine is different and even a slight difference in engine specs can cause issues and even engine Damage. Especially on Turbo motors.   If you need tuning help, I custom make MS Baseline Tunes from scratch and also supply remote tuning help.  I do charge a reasonable fee for Remote Tuning and have helps several members here and at other forums. You can PM me for more info.

 

5: SoftoZpz ( Hussein ) on the Vendors forum makes custom harnesses and can pre-build MS ECU units for you. He also is a distributor for 14point7 WB controllers ( Very good product. ) and IDash.  

 

Richard

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9 hours ago, madkaw said:

As much as I’d like to do ITB’s - I chickened out and went with a stock intake . Why? Because I have/had so much to learn about tuning and I didny want it to be overwhelming and not enjoy my ride .

that being said - maybe you should find a stock intake and I would recommend a Maxima head . Everything just bolts together and you can concentrate on learning to tune with MS instead of fighting an ITB set up


I read a bit about the maxima head, the N47 right? I was looking at a few threads about it, specifically this one. And there is discussion about having to notch the block to make it work? Is this the case for the L26 as well? What head gasket would I need to run and what compression numbers would I be looking for?


Richard, regarding injectors, I was going to go with newer high impedance Bosch units. Something along these lines. I'll definitely get in contact for tuning help when I get closer to start-up.

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One thing to consider is to hire a tuner to dial it all in. I had Jeff Linfert setup and tune my DOHC with ITBs and he did it all via email. Spending a little money up front getting things setup by a pro and then learning how to tweak may save you some frustration and get you on the road a lot quicker. I would find one in your area if you want to do dyno tuning as well.

 

Derek

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Yes , the Maxima head has the bigger 35mm exhaust valve , so probably need to notch bore slightly. Just throw whatever Felpro calls for for that year - CR shouldn’t be an issue . If you could afford to throw the bigger 44mm intake valves in then I would do that also. 

I just suggested this head because it is notched for injectors and you can bolt any stock EFI intake to it . Besides the fact it has the ideal chamber . 

I’m running Audi 1.8 26lb injectors myself

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3 hours ago, munters said:

I wonder why nobody tries the jenvey Heritage ?


In my eyes, mainly cost. They are what? 1600 euros for set of 3? And you get injectors, fuel rail, and TPS. Still need a DCOE manifold to bolt it to, throttle linkage, an ECU, and all the associated sensors. On the other hand, the triumph throttle body setup gets you the same thing for $200 used tops. Still need a manifold,throttle linkage, an ecu, and associated sensors. I love the look of the jenvey, just can't justify the cost.

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To swap to the 82-83 L28ET distributor (for cam position / crank position sensors) into an L26, do I just need the distributor, and the drive shaft? Or do I also need to swap my oil pump? Or will it work with my L26 oil pump with the new shaft?

The three parts I'm looking at:
Shaft
Distributor
Gaskets

Do I need this oil pump as well?
Oil pump

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